Table 1.

Physical characteristics (average values) of the experimental samples (before etching, as-produced amorphous membrane).

Samples and forming conditions	Pore diameter, d (nm)	Cell diametera, D (nm)	PAA thickness, H (µm)	Aspect ratio, n = D/d	Barrier layer thickness, В (nm)	Wall thickness, W (nm)
(type I) H2C2O4, 50 V	44	125 (115)	65	145	45.4	40.5
(type II) H2C2O4, 40 V	40	105 (110)	46	115	37.5	33.5
(type III) H2SO4, 20 V	25	45 (50)	75	300	15	14

^aCalculated values are given with the mean values calculated based on SEM photos given in brackets.